Dogwood trees are highly esteemed for their attractive appearance and adaptability, which has made them a top choice among both horticulturists and tree lovers.
However, like any tree, dogwoods can sometimes host other organisms, such as lichen. If you’ve noticed a green, leafy, or crusty growth on your dogwood, you may be dealing with lichen.
Lichen on a dogwood tree is not harmful. Lichen is a symbiotic organism that does not harm the tree on which it grows. In fact, the presence of lichen often indicates good air quality and can enhance biodiversity. However, excessive lichen growth may be a sign of other underlying tree health issues.
In the following, we will explore what lichen is, its role in the environment, the different types of lichen you might find on a dogwood tree, and how lichen relates to tree health.
You’ll also learn about the factors that affect lichen growth and how to remove lichen if desired.
- Lichen is a symbiotic organism that is generally harmless to dogwood trees. It can indicate good air quality and contribute to biodiversity.
- There are several types of lichen that can grow on dogwood trees, including foliose, fruticose, and crustose lichen.
- While lichen itself does not harm trees, heavy lichen growth can sometimes indicate underlying tree health issues.
- If desired, lichen can be removed by gently scrubbing it off with a soft brush and a mild solution of water and dish soap.
Even with dedicated care, dogwood trees can experience a variety of issues. To learn more about protecting your trees and spotting issues early, be sure to read my article, Common Dogwood Problems.
Understanding Lichen on Trees
Lichen is a fascinating organism that often goes unnoticed but plays a crucial role in our environment. Here’s a closer look at what lichen is and its role in the environment:
What Is Lichen?
Lichen is a symbiotic organism made up of two or more different organisms: a fungus and one or more photosynthetic partners, usually algae or cyanobacteria.
The fungus provides the structure and protects the photosynthetic partner, which in turn provides food for the fungus through photosynthesis.
This symbiotic relationship allows lichen to survive in a wide range of environments from the arctic tundra to the desert.
Lichen can come in various forms, from leafy foliose lichen or shrubby fruticose lichen to crusty crustose lichen.
The type of lichen you find on your dogwood tree can depend on various factors, including the tree’s health, the local environment, and the specific species of fungus and photosynthetic partner involved.
Lichen’s Role in the Environment
Lichen plays several important roles in the environment. It helps break down rocks into soil, absorbs and stores water, and provides food and habitat for a variety of animals.
Lichen can also serve as an indicator of air quality because it is sensitive to air pollution. A healthy population of lichen often indicates clean, unpolluted air.
Types of Lichen on Dogwood Trees
There are several types of lichen that you might find on a dogwood tree. Here’s a closer look at some of the most common types:
Foliose lichen is leaf-like in appearance, with a flat, lobed body that is loosely attached to the bark of the tree.
It comes in a variety of colors, from greens and grays to yellows and oranges. Foliose lichen is common on dogwood trees and is generally harmless.
Fruticose lichen is shrubby or hair-like in appearance and can either be loosely attached to the tree or hang down in long strands.
This type of lichen is less common on dogwood trees but can occur in some environments.
Crustose lichen forms a thin, crust-like layer that is tightly attached to the tree’s bark. It is often brightly colored, with hues ranging from white and yellow to orange and red.
Crustose lichen is common on dogwood trees and, like other lichens, is generally harmless.
Lichen and Tree Health
While lichen itself is not harmful to trees, its presence can sometimes indicate other issues related to tree health.
Lichen Does Not Hurt Trees
Lichen is not a parasite and does not harm the trees on which it grows. It gets its nutrients from the air and rain, not from the tree.
Therefore, you don’t need to remove lichen from your dogwood tree for the sake of the tree’s health.
Lichen Growth May Indicate Tree Health Issues
While lichen itself does not harm trees, heavy lichen growth can sometimes be a sign of other underlying tree health issues.
For example, if a tree is stressed or declining, it may not produce as much foliage, allowing more light to reach the lichen and promoting its growth.
Therefore, if you notice a sudden increase in lichen growth on your dogwood tree, it may be worth checking the tree for other signs of stress or disease.
Indicates Good Air Quality
Lichen is sensitive to air pollution, especially sulfur dioxide. Therefore, a healthy population of lichen can be a good indicator of clean, unpolluted air.
Lichen provides food and habitat for a variety of animals, including insects, birds, and small mammals.
It also contributes to biodiversity by breaking down rocks into soil and cycling nutrients in the ecosystem.
Factors Affecting Lichen Growth
Several factors can affect lichen growth on dogwood trees, including light, moisture, air quality, and the tree’s health.
Lichen generally prefers locations with plenty of light and moisture but can adapt to a wide range of conditions.
It is sensitive to air pollution, so lichen growth can be less abundant in polluted environments.
As mentioned earlier, lichen growth can also be influenced by the health of the tree, with more lichen often growing on stressed or declining trees.
Factors That Inhibit Lichen Growth
Just as certain factors promote lichen growth, others can inhibit it. These include lack of light, dry conditions, air pollution, and poor bark quality.
For example, if a dogwood tree is healthy and produces a full canopy of leaves, this can limit the amount of light reaching the lichen and inhibit its growth.
Similarly, if the tree’s bark is frequently disturbed, for example, by animals or mechanical damage, this can make it difficult for lichen to establish.
How To Remove Lichen
While lichen is generally not harmful to dogwood trees, there may be times when you want to remove it, such as for aesthetic reasons or if the lichen growth is excessive.
To remove lichen, you can gently scrub it off with a soft brush. Be careful not to damage the tree’s bark. For stubborn lichen, you can use a mild solution of water and dish soap.
However, it’s important to note that removing the lichen will not solve any underlying tree health issues that may be promoting its growth.
Should Lichen Be Removed?
As lichen does not harm trees and can contribute to biodiversity, it generally does not need to be removed.
However, if the lichen growth is excessive or you prefer the look of your dogwood tree without lichen, you can choose to remove it.
Where Do Lichens Grow?
Lichens can grow in a wide range of environments, from the arctic tundra to the desert. They are commonly found on trees, rocks, and soil.
On dogwood trees, lichen typically grows on the bark, often on the trunk and larger branches.
Lichen on a dogwood tree is a fascinating organism that is generally harmless to the tree. Its presence can indicate good air quality and contribute to biodiversity.
However, heavy lichen growth can sometimes be a sign of underlying tree health issues. Inspect your tree regularly for issues, and correct any you find promptly.
Providing good care for your dogwood necessitates being knowledgeable about common issues and problems. Be sure to learn about these topics: